Maybe they'll be like Gotham season regulars who get less than 10 minutes of screentime over the entire season.
True Blood was the king of making everybody a series regular. That show was only 80 episodes but managed to have 55 different actors in the opening credits throughout it's run.
Yeah I thought it was funny that dent's actor was a regular despite barely showing up at all. Part of the weird charm that is Gotham season 2.